The Explain Plan tab displays the execution plan for a query.
To view the execution plan for a query filter, click on the collection on the left hand pane, then click Explain Plan.
You can view the explain stages in a tree format. Each stage of the pipeline appears as a node on the tree. This makes sharded cluster outputs easier to understand and visualize.
You can also view the explain details in raw JSON format:
To learn more about execution plans, see the MongoDB documentation.